A sugar substitute is a food additive that provides a sweettaste like that of sugar while containing significantly less food energy. Some sugar substitutes are produced by nature, and others produced synthetically. Those that are not produced by nature are, in general, called artificial sweeteners. In 2017, sucralose was the most common sugar substitute used in manufacturing of foods and beverages, having 30% of the global market projected to become $2.8 billion in collective value by 2021.[1]

When sweeteners are provided for restaurant customers to add to beverages such as tea and coffee, they are often available in paper packets that can be torn and emptied. In North America, the colors are typically white for sucrose, blue for aspartame, pink for saccharin,[note 1] yellow for sucralose (United States) or cyclamate (Canada), tan for turbinado, orange for monk fruit extract, and green for stevia.[2]

A class of sugar substitutes is known as high-intensity sweeteners. These are compounds with many times the sweetness of sucrose, common table sugar. As a result, much less sweetener is required and energy contribution is often negligible. The sensation of sweetness caused by these compounds (the "sweetness profile") is sometimes notably different from sucrose, so they are often used in complex mixtures that achieve the most natural sweet sensation.

If the sucrose (or other sugar) that is replaced has contributed to the texture of the product, then a bulking agent is often also needed. This may be seen in soft drinks or sweet teas that are labeled as "diet" or "light" that contain artificial sweeteners and often have notably different mouthfeel, or in table sugar replacements that mix maltodextrins with an intense sweetener to achieve satisfactory texture sensation.

In the United States, six high-intensity sugar substitutes have been approved for use: aspartame, sucralose, neotame, acesulfame potassium (Ace-K), saccharin, and advantame.[3]Food additives must be approved by the FDA,[3] and sweeteners must be proven as safe via submission by a manufacturer of a GRAS document.[4] The conclusions about GRAS are based on a detailed review of a large body of information, including rigorous toxicological and clinical studies.[4] GRAS notices exist for two plant-based, high-intensity sweeteners: steviol glycosides obtained from stevia leaves (Stevia rebaudiana) and extracts from Siraitia grosvenorii, also called Luo Han Guo or monk fruit.[3]

Cyclamates are used outside the United States, but are prohibited from manufacturing as a sweetener within the United States.[3] The majority of sugar substitutes approved for food use are artificially synthesized compounds. However, some bulk plant-derived sugar substitutes are known, including sorbitol, xylitol and lactitol. As it is not commercially viable to extract these products from fruits and vegetables, they are produced by catalytichydrogenation of the appropriate reducing sugar. For example, xylose is converted to xylitol, lactose to lactitol, and glucose to sorbitol.

Sorbitol, xylitol and lactitol are examples of sugar alcohols (also known as polyols). These are, in general, less sweet than sucrose but have similar bulk properties and can be used in a wide range of food products. Sometimes the sweetness profile is fine-tuned by mixing with high-intensity sweeteners.

In the United States, the FDA provides guidance for manufacturers and consumers about the daily limits for consuming high-intensity sweeteners, a measure called Acceptable Daily Intake (ADI).[3] During their premarket review for all of the high-intensity sweeteners approved as food additives, FDA established an ADI defined as an amount in milligrams per kilogram of body weight per day (mg/kg bw/d), indicating that a high-intensity sweetener does not cause safety concerns if estimated daily intakes are lower than the ADI.[5] FDA states: "An ADI is the amount of a substance that is considered safe to consume each day over the course of a person’s lifetime." For stevia (specifically, steviol glycosides), an ADI was not derived by the FDA, but by the Joint Food and Agricultural Organization/World Health Organization Expert Committee on Food Additives, whereas an ADI has not been determined for monk fruit.[5] FDA also published estimates of sweetness intensity, called a multiplier of sweetness intensity (MSI) as compared to table sugar.

For the sweeteners approved as food additives, the ADIs in milligrams per kilogram of body weight per day are:[5]

Dental care – Carbohydrates and sugars usually adhere to the tooth enamel, where bacteria feed upon them and quickly multiply.[6] The bacteria convert the sugar to acids that decay the teeth. Sugar substitutes, unlike sugar, do not erode teeth as they are not fermented by the microflora of the dental plaque. A sweetener that may benefit dental health is xylitol, which tends to prevent bacteria from adhering to the tooth surface, thus preventing plaque formation and eventually decay. A Cochrane review, however, found only low-quality evidence that xylitol in a variety of dental products actually has any benefit in preventing tooth decays in adults and children.[6]

Diabetes mellitus – People with diabetes have difficulty regulating their blood sugar levels, and need to limit their sugar intake. Many artificial sweeteners allow sweet tasting food without increasing blood glucose. Others do release energy but are metabolized more slowly, preventing spikes in blood glucose. A concern, however, is that overconsumption of foods and beverages made more appealing with sugar substitutes may increase risk of developing diabetes.[7] A 2014 systematic review showed that a 330ml/day (an amount little less than the standard U.S can size) consumption of artificially sweetened beverages lead to increased risks of type 2 diabetes. [8] A 2015 meta-analysis of numerous clinical studies showed that habitual consumption of sugar sweetened beverages, artificially sweetened beverages, and fruit juice increased the risk of developing diabetes, although with inconsistent results and generally low quality of evidence.[7] A 2016 review also showed positive correlations between artificially sweetened beverages and diabetes, although again, reported as biased.[8]

Reactive hypoglycemia – Individuals with reactive hypoglycemia will produce an excess of insulin after quickly absorbing glucose into the bloodstream. This causes their blood glucose levels to fall below the amount needed for proper body and brain function. As a result, like diabetics, they must avoid intake of high-glycemic foods like white bread, and often use artificial sweeteners for sweetness without blood glucose.

Cost and shelf life – Many sugar substitutes are cheaper than sugar in the final food formulation. Sugar substitutes are often lower in total cost because of their long shelf-life and high sweetening intensity. This allows sugar substitutes to be used in products that will not perish after a short period of time.[9]

The world's most commonly used artificial sweetener,[1]sucralose is a chlorinated sugar that is about 600 times as sweet as sugar. It is produced from sucrose when three chlorine atoms replace three hydroxyl groups. It is used in beverages, frozen desserts, chewing gum, baked goods, and other foods. Unlike other artificial sweeteners, it is stable when heated and can therefore be used in baked and fried goods. Discovered in 1976, the FDA approved sucralose for use in 1998.[10]

Most of the controversy surrounding Splenda, a sucralose sweetener, is focused not on safety but on its marketing. It has been marketed with the slogan, "Splenda is made from sugar, so it tastes like sugar." Sucralose is prepared from either of two sugars, sucrose or raffinose. With either base sugar, processing replaces three oxygen-hydrogen groups in the sugar molecule with three chlorine atoms.[11]

The "Truth About Splenda" website was created in 2005 by The Sugar Association, an organization representing sugar beet and sugar cane farmers in the United States,[12] to provide its view of sucralose. In December 2004, five separate false-advertising claims were filed by the Sugar Association against Splenda manufacturers Merisant and McNeil Nutritionals for claims made about Splenda related to the slogan, "Made from sugar, so it tastes like sugar". French courts ordered the slogan to no longer be used in France, while in the U.S. the case came to an undisclosed settlement during the trial.[11]

There are few safety concerns pertaining to sucralose[13] and the way sucralose is metabolized suggests a reduced risk of toxicity. For example, sucralose is extremely insoluble in fat and, thus, does not accumulate in fatty tissues; sucralose also does not break down and will dechlorinate only under conditions that are not found during regular digestion (i.e., high heat applied to the powder form of the molecule).[14] Only about 15% of sucralose is absorbed by the body and most of it passes out of the body unchanged.[14]

Aspartame was discovered in 1965 by James M. Schlatter at the G.D. Searle company. He was working on an anti-ulcer drug and accidentally spilled some aspartame on his hand. When he licked his finger, he noticed that it had a sweet taste. Torunn Atteraas Garin oversaw the development of aspartame as an artificial sweetener. It is an odorless, white crystalline powder that is derived from the two amino acids aspartic acid and phenylalanine. It is about 200 times as sweet as sugar and can be used as a tabletop sweetener or in frozen desserts, gelatins, beverages, and chewing gum. When cooked or stored at high temperatures, aspartame breaks down into its constituent amino acids. This makes aspartame undesirable as a baking sweetener. It is more stable in somewhat acidic conditions, such as in soft drinks. Though it does not have a bitter aftertaste like saccharin, it may not taste exactly like sugar. When eaten, aspartame is metabolized into its original amino acids. Because it is so intensely sweet, relatively little of it is needed to sweeten a food product, and is thus useful for reducing the number of calories in a product.

The safety of aspartame has been studied extensively since its discovery with research that includes animal studies, clinical and epidemiological research, and postmarketing surveillance,[15] with aspartame being one of the most rigorously tested food ingredients to date.[16] Aspartame has been subject to multiple claims against its safety, including supposed links to cancer as well as complaints of neurological or psychiatric side effects.[17] Multiple peer-reviewed comprehensive review articles and independent reviews by governmental regulatory bodies have analyzed the published research on the safety of aspartame and have found aspartame is safe for consumption at current levels.[15][17][18][19] Aspartame has been deemed safe for human consumption by over 100 regulatory agencies in their respective countries,[19] including the UK Food Standards Agency,[20] the European Food Safety Authority (EFSA)[21] and Canada's Health Canada.[22]

Apart from sugar of lead (used as a sweetener in ancient through medieval times before the toxicity of lead was known), saccharin was the first artificial sweetener and was originally synthesized in 1879 by Remsen and Fahlberg. Its sweet taste was discovered by accident. It had been created in an experiment with toluene derivatives. A process for the creation of saccharin from phthalic anhydride was developed in 1950, and, currently, saccharin is created by this process as well as the original process by which it was discovered. It is 300 to 500 times as sweet as sugar (sucrose) and is often used to improve the taste of toothpastes, dietary foods, and dietary beverages. The bitter aftertaste of saccharin is often minimized by blending it with other sweeteners.

Fear about saccharin increased when a 1960 study showed that high levels of saccharin may cause bladder cancer in laboratory rats. In 1977, Canada banned saccharin due to the animal research. In the United States, the FDA considered banning saccharin in 1977, but Congress stepped in and placed a moratorium on such a ban. The moratorium required a warning label and also mandated further study of saccharin safety.

Subsequent to this, it was discovered that saccharin causes cancer in male rats by a mechanism not found in humans. At high doses, saccharin causes a precipitate to form in rat urine. This precipitate damages the cells lining the bladder (urinary bladder urothelial cytotoxicity) and a tumor forms when the cells regenerate (regenerative hyperplasia). According to the International Agency for Research on Cancer, part of the World Health Organization, "Saccharin and its salts was [sic] downgraded from Group 2B, possibly carcinogenic to humans, to Group 3, not classifiable as to carcinogenicity to humans, despite sufficient evidence of carcinogenicity to animals, because it is carcinogenic by a non-DNA-reactive mechanism that is not relevant to humans because of critical interspecies differences in urine composition."

In 2001, the United States repealed the warning label requirement, while the threat of an FDA ban had already been lifted in 1991. Most other countries also permit saccharin, but restrict the levels of use, while other countries have outright banned it.

The EPA has officially removed saccharin and its salts from their list of hazardous constituents and commercial chemical products. In a 14 December 2010 release, the EPA stated that saccharin is no longer considered a potential hazard to human health.

Stevia has been widely used as a natural sweetener in South America for centuries and in Japan since 1970. It has zero glycemic index and zero calories,[26] and it is becoming popular in many other countries. In 1987, the FDA issued a ban on stevia because it had not been approved as a food additive, although it continued to be available as a dietary supplement.[27] After being provided with sufficient scientific data regarding side-effects of using stevia as a sweetener from companies such as Cargill and Coca-Cola, the FDA gave a "no objection" approval for generally recognized as safe (GRAS) status in December 2008 to Truvia, a blend of rebaudioside A and erythritol[28][29] (developed by Cargill and The Coca-Cola Company), as well as PureVia (developed by PepsiCo and the Whole Earth Sweetener Company, a subsidiary of Merisant),[30]
both of which use rebaudioside A derived from the stevia plant. In Australia, the brand Vitarium uses Natvia, a natural stevia sweetener, in a range of sugar-free children's milk mixes.[31]

Acesulfame potassium (Ace-K) is 200 times sweeter than sucrose (common sugar), as sweet as aspartame, about two thirds as sweet as saccharin, and one third as sweet as sucralose. Like saccharin, it has a slightly bitter aftertaste, especially at high concentrations. Kraft Foods has patented the use of sodium ferulate to mask acesulfame's aftertaste. Acesulfame potassium is often blended with other sweeteners (usually aspartame or sucralose), which give a more sucrose-like taste, whereby each sweetener masks the other's aftertaste and also exhibits a synergistic effect in which the blend is sweeter than its components.

Unlike aspartame, acesulfame potassium is stable under heat, even under moderately acidic or basic conditions, allowing it to be used as a food additive in baking or in products that require a long shelf life. In carbonated drinks, it is almost always used in conjunction with another sweetener, such as aspartame or sucralose. It is also used as a sweetener in protein shakes and pharmaceutical products, especially chewable and liquid medications, where it can make the active ingredients more palatable.

Lead acetate (sometimes called sugar of lead) is a toxic artificial sugar substitute made from lead that is of historical interest because of its widespread use in the past, such as by ancient Romans.[32] The use of lead acetate as a sweetener eventually produced lead poisoning in any individual ingesting it habitually. Lead acetate was abandoned as a food additive throughout most of the world after the high toxicity of lead compounds became apparent.

Mogrosides, extracted from monk fruit and commonly called luo han guo, are recognized as safe for human consumption and are used in some commercial products in the United States.[33][34] As of 2017, it is not a permitted sweetener in the European Union,[35] although it is allowed as a natural flavor at concentrations where it does not function as a sweetener.[34] In 2017, a Chinese company requested a scientific review of its mogroside product by the European Food Safety Authority.[36] Some products incorporating it are Nestlé's Milo in Asia and certain Kellogg cereals in the United States.[37] It is also the basis of McNeil Nutritionals's tabletop sweetener Nectresse in the United States and Norbu Sweetener in Australia.[37]

Numerous reviews have concluded that outcomes from weight gain and non-nutritive sweetener usage remain inconsistent and inconclusive.[38] A 2010 review of epidemiological studies concluded there is a possible association between consumption of artificially sweetened beverages and weight gain in children, but the quality of the studies was weak and no clear cause and effect relationship could be determined.[39] A 2016 review reported findings with no significant association between body weight and non-nutritive sweetener consumption,[40] while a 2017 review did not find evidence supporting the use of non-nutritive sweeteners for weight loss.[41]

A 2015 review of the literature found that there was no clear evidence for a link between the use of artificial sweeteners and an increased risk of cancer.[43]

A 2017 review found that although there are reports of a couple of studies signifying increased risks of cancer through the use of sugar substitutes (ie. colorectal cancer), a vast majority of studies yielded similar results to that of 2015. An extensive array of studies (ie. case-control, primary, and observational studies), studying varying cancer types such as lymphomas, hematological malignancies, urinary tract, bladder, pancreatic, biliary tract, and breast cancer displayed no significant association between this disease and artificial sweeteners. [44]

Sugar alcohols, or polyols, are sweetening and bulking ingredients used in manufacturing of foods and beverages.[45] As a sugar substitute, they supply less calories (about a half to one-third less calories) than sugar, are converted to glucose slowly, and do not spike increases in blood glucose.[45][46]

Eating natural sugars like glucose and sucrose instead of a sugar substitute can have negative health effects. The consumption of added sugars has been positively associated with multiple measures known to increase cardiovascular disease risk amongst adolescents as well as adults.[47] The calories contained in sugar-sweetened beverages contribute to increases in body weight and body fat, and replacement of sugar by artificial sweeteners reduces weight.[48]Obesity contributes to diabetes and cardiovascular disease. Glucose has a high glycemic index, sucrose medium, and fructose low. There is evidence that sugar-sweetened beverages "may increase the risk of metabolic syndrome and type 2 diabetes not only through obesity but also by increasing dietary glycemic load, leading to insulin resistance, β-cell dysfunction, and inflammation," according to a 2010 meta-analysis.[49]

There is "convincing evidence from human intervention studies, epidemiological studies, animal studies and experimental studies, for an association between the amount and frequency of free sugars intake and dental caries" while other sugar (complex carbohydrate) consumption is normally associated with a lower rate of dental caries, according to the World Health Organization.[50]

A 2013 review found that there is insufficient evidence to suggest that replacing dietary sugar with non-caloric sweeteners alone is beneficial for energy balance, weight loss, or diabetes risk factors.[51] The review found that restricting calories is more important than avoidance of sugar for weight management, and that non-caloric sweeteners may be useful for managing blood sugar in people with diabetes.[51]